Profiling hardness and microstructural evolution in the soft zone of 1.25Cr-0.5Mo heat-resistant steel subjected to varied creep durations

Simulated welding has been employed to precisely locate and track the soft zone of 1.25Cr-0.5Mo heat resistant steel. Hardness and microstructural variations in the soft zone subjected to designed creep durations have been systematically explored. It has been demonstrated that, as the creep duration increases, the hardness of the soft zone gradually increases, which is primarily driven by the grain size reduction of equiaxed ferrites. In addition, population of carbide precipitates and accumulation of geometrically necessary dislocations also contribute synergistically to hardness dip.

Automated summary

Simulated welding technique was used to accurately locate and track the soft zone of 1.25Cr-0.5Mo heat resistant steel. The hardness and microstructural changes in the soft zone with different creep durations were systematically investigated. It was found that the hardness of the soft zone gradually increased with longer creep durations, mainly due to the reduction in grain size of equiaxed ferrites. The presence of carbide precipitates and accumulation of geometrically necessary dislocations also synergistically contributed to the decrease in hardness.